1. Technology Field
The invention generally relates to a data writing method, and more particularly, to a data writing method for writing data that has a quantity smaller than a predetermined value into a rewritable non-volatile memory module, a memory controller, and a memory storage device.
2. Description of Related Art
Along with the widespread of digital cameras, cell phones, and MP3 players in recently years, the consumers' demand to storage media has increased drastically. Rewritable non-volatile memory (for example, flash memory) is very suitable for aforementioned portable multimedia devices due to its many characteristics such as data non-volatility, low power consumption, small volume, and non-mechanical structure.
Generally, a rewritable non-volatile memory module includes a plurality of physical erasing units, and these physical erasing units have to be erased before being used for writing new data. A plurality of logical addresses is mapped to part of the physical erasing units, and a host system issues commands for accessing these logical addresses to write data into the rewritable non-volatile memory module. If most physical erasing units contain data and the host system desires to write data again, valid data in the physical erasing units has to be merged to release spare physical erasing units. However, if the valid data in a physical erasing unit belongs to different logical addresses, the valid data belonging to these multiple logical addresses has to be merged to release a spare physical erasing unit. If it takes too long to merge the valid data, the time limit for the host system to wait for a write success message may be exceeded. Thereby, how to avoid merging too much valid data at each time and prevent the time for a host system to wait for a write success message from exceeding its upper limit is one of the subjects in the industry.
Nothing herein should be construed as an admission of knowledge in the prior art of any portion of the present invention. Furthermore, citation or identification of any document in this application is not an admission that such document is available as prior art to the present invention, or that any reference forms a part of the common general knowledge in the art.